Early development of the cerebellar circuits

我的研究计划的总体目标是了解驱动早期小脑发育和回路形成的机制。小脑是大脑的一部分，对协调运动、情绪和认知非常重要。两种类型的神经元是调节小脑功能的中枢：小脑核团(CN)神经元和浦肯野细胞(PC)。CN神经元和PC是小脑早期发育过程中仅存的神经元群体。尽管CN是小脑的主要输出神经元，但对它们在早期神经回路发育中的形成和连接知之甚少。我们已经发现，表达SNCA/OTX2/p75NTR的CN神经元的一部分(以下简称A细胞)起源于中脑，并迁移到发育中的小脑。我们还提供了新的信息，三叉神经向小脑原基投射先锋轴突，靶向A细胞。这些数据提出了这样一种可能性，即早期小脑回路的发育依赖于三叉神经，而不是传统认为的前庭神经。我的研究将探讨早期小脑回路如何调节小脑的形态发生，并为CN神经元提供迁移底物。为了实现这一目标，我将使用体外和体内模型的组合，包括小鼠遗传学、胚胎和原代小脑培养、整体和切片免疫组织化学、原位杂交(RNAScope)、Western blotting、神经元束追踪，以及神经元迁移的3D微工程模型。需要回答的重要问题包括：A细胞是否起源于中脑神经脊？菱形唇状核神经元是否使用A细胞/先锋轴突进行迁移？A细胞在发育中的小脑中的命运是什么？这项拟议的研究将加强我们对早期先锋轴突和它们的目标神经元如何在发育中的小脑中扮演内在组织者角色的理解。我将调查A细胞是否暂时存在，以及三叉神经测试中是否存在先锋轴突，如果它们建立了小脑回路。我提出的机制偏离了传统的模式。我还将调查这些新的A细胞/先锋轴突组合是否为菱形唇源性细胞向其目的地提供了迁移底物。阐明这种内在组织者的作用将回答有关早期小脑形态发生和发育的基本生物学问题。拟议的研究将被用作在发育神经生物学的广泛领域培训HQP和神经科学领域的研究科学家的工具。

The overall goal of my research program is to understand the mechanism driving early cerebellar development and circuit formation. The cerebellum is a part of the brain that is important for coordinating movements, emotion and cognition. Two types of neurons are central in regulating cerebellar function: cerebellar nuclei (CN) neurons and Purkinje cells (Pcs). The CN neurons and Pcs are the only neuronal populations that exist during early cerebellar development. Although the CN are the main output neurons of the cerebellum, little is known about their formation and their connectivity in early neural circuit development. We have discovered that a subset of CN neurons that express SNCA/Otx2/P75ntr (hereafter called “A-cells”) originates from the mesencephalon and migrates into the developing cerebellum. We have also provided novel information that the trigeminal nerve projects pioneer axons to the cerebellar primordium, targets A-cells. These data raise the possibility that early cerebellar circuit development depends on the trigeminal nerve, not the vestibular nerve as traditionally thought. My research will investigate how early cerebellar circuits regulate cerebellar morphogenesis and provide a migratory substrate for CN neurons. To achieve this goal I will use a combination of in vitro and in vivo models including mouse genetics, embryonic and primary cerebellar culture, whole mount and section immunohistochemistry, in situ hybridization (RNAscope), Western blotting, neuronal tract tracing, and a 3D micro-engineered model of neuronal migration. Important questions to be answered include: Do A-cells originate from mesencephalic neural crest? Do rhombic lip-derived CN neurons use A-cells/pioneer axons for migration? What is the fate of A-cells in the developing cerebellum? The proposed research will enhance our understanding of how early pioneer axons and their target neurons play intrinsic organizer roles in the developing cerebellum. I will investigate if A-cells are temporarily present and with pioneer axons from the trigeminal nerve test if they establish cerebellar circuit. The mechanism I propose deviates from the traditional model. I will also investigate if these new A-cells/pioneer axon combination provide a migratory substrate for the rhombic lip-derived cells to their destination. Elucidating the role of this intrinsic organizer will answer key questions about the basic biology of early cerebellar morphogenesis and development. The proposed research will be used as a vehicle to train HQP in the broad areas of developmental neurobilogy and for research scientists in the field of neuroscience.